While performing some TDDFT calculations I noticed a strange behavor of the TDOS. I have calculated the static TDOS and the TDOS_TS.OUT using exactly the same set of parameters. I expected that the TDOS_TS000001.OUT (at the 1st time step of the simulation) will coincide with the static one. Actually, the TDOS at each time instances before the arrival of the field should be equal to static one.
However, that is true for the occupied part only, E<0.
For all energies E>0 the TD DOS is essentially zero, and it only becomes non-vanishing after the arrival of the field.
(Please see the attached figure. The curves labed with ts=... are the TDOS at particular time steps, with ts=1 the 1st step, while the points are the static TDOS).
So, is this something I should have expected?
Meaning the TDOS_TS is not exactly the same as the static TDOS as I thought?
Otherwise, it means there is something wrong with my TDDFT calculation.
I believe the static TDOS is well converged, with respect to kpoints and empty states, but is it possible that it is not enough for the TD simulation?
Within TDDFT only the occupied DOS is calculated. For more details on how it is done please see: Ultrafast laser induced local magnetization dynamics in Heusler compounds, P Elliott, T Müller, JK Dewhurst, S Sharma, EKU Gross, Scientific Reports 6, 38911 (2016).
Best
Sangeeta
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Thank you for your response.
If I may ask. I see non-vanishing DOS for E>0 after the arrival of the pulse due to the excited electrons, which is consistent with the lowering of the DOS for E<0.
Is that correct?
Best,
Myron
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Any possibility to obtain time dependent unoccupied density of states in ELK or anyother similar all electron FP-LAPW codes? They are needed for simulating real-time evolution of X-ray absorption in metallic alloys.
Further, may I ask why unoccupied DOS can't be calculated on same footing as occupied DOS in time evolution run in TDDFT (I don't know internal details of TDDFT impelementation in ELK)?
Regards
Naman
Last edit: NAMAN AGARWAL 2021-10-29
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Dear all,
While performing some TDDFT calculations I noticed a strange behavor of the TDOS. I have calculated the static TDOS and the TDOS_TS.OUT using exactly the same set of parameters. I expected that the TDOS_TS000001.OUT (at the 1st time step of the simulation) will coincide with the static one. Actually, the TDOS at each time instances before the arrival of the field should be equal to static one.
However, that is true for the occupied part only, E<0.
For all energies E>0 the TD DOS is essentially zero, and it only becomes non-vanishing after the arrival of the field.
(Please see the attached figure. The curves labed with ts=... are the TDOS at particular time steps, with ts=1 the 1st step, while the points are the static TDOS).
So, is this something I should have expected?
Meaning the TDOS_TS is not exactly the same as the static TDOS as I thought?
Otherwise, it means there is something wrong with my TDDFT calculation.
I believe the static TDOS is well converged, with respect to kpoints and empty states, but is it possible that it is not enough for the TD simulation?
Best,
Myron
Last edit: Myron Kapetanakis 2019-08-01
Hi Myron,
Within TDDFT only the occupied DOS is calculated. For more details on how it is done please see: Ultrafast laser induced local magnetization dynamics in Heusler compounds, P Elliott, T Müller, JK Dewhurst, S Sharma, EKU Gross, Scientific Reports 6, 38911 (2016).
Best
Sangeeta
Dear Sangeeta,
Thank you for your response.
If I may ask. I see non-vanishing DOS for E>0 after the arrival of the pulse due to the excited electrons, which is consistent with the lowering of the DOS for E<0.
Is that correct?
Best,
Myron
Dear Sangeeta,
Any possibility to obtain time dependent unoccupied density of states in ELK or anyother similar all electron FP-LAPW codes? They are needed for simulating real-time evolution of X-ray absorption in metallic alloys.
Further, may I ask why unoccupied DOS can't be calculated on same footing as occupied DOS in time evolution run in TDDFT (I don't know internal details of TDDFT impelementation in ELK)?
Regards
Naman
Last edit: NAMAN AGARWAL 2021-10-29